Queen's Indian Defense: Classical Variation, Traditional Variation, Main Line

The Queen's Indian Defense: Classical Variation, Traditional Variation, Main Line is a chess opening classified under ECO code E19 in the Indian Defences family, where Black responds to 1.d4 with 1...Nf6, including the Nimzo-Indian, Queen's Indian, and King's Indian. It is reached after 9 moves: 1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 Ne4 8. Qc2 Nxc3 9. Qxc3. The resulting position leaves black to move.